Diferentes linhagens de Bacillus thuringiensis Berliner têm provado ser poderoso inseticida biológico contra larvas de várias ordens de insetos. Dada a importância epidemiológica das moscas do gênero Chrysomya Robineau-Desvoidy na produção de miíases cutâneas secundárias e transmissão mecânica de agentes patogênicos, avaliou-se a atividade de duas linhagens de B. thuringiensis (LFB-FIOCRUZ 907 e LFB-FIOCRUZ 856) sobre larvas de Chrysomya putoria (Wiedemann). A linhagem LFB-FIOCRUZ 907 foi testada em quatro diferentes concentrações misturadas à dieta e a linhagem LFB-FIOCRUZ 856 em três concentrações. As larvas de C. putoria apresentaram sensibilidade ao tratamento com a linhagem LFB-FIOCRUZ 907, nas concentrações testadas, sendo a concentração mais alta a de maior eficiência, causando maior mortalidade e reduzindo mais intensamente o peso larval e a taxa de emergência dos adultos. A linhagem LFB-FIOCRUZ 856 apresentou toxicidade muito baixa, redizindo ligeiramente a emergência dos adultos na concentração de 326 mg/ 25 g e o peso larval nas concentrações de 326 mg/ 25 g e 86 mg/ 25 g.

Different strains of Bacillus thuringiensis Berliner were proved to be a powerful biologic insecticide against larvae of several insect orders. Due to the epidemiological importance of blowflies of the Chrysomya Robineau-Desvoidy genus in the production of secondary cutaneous myiasis and mechanic transmission of pathogenic agents, the performance of two strains of B. thuringiensis (LFB-FIOCRUZ 907 and LFB-FIOCRUZ 856) was tested against larvae of Chrysomya putoria (Wiedemann). The LFB-FIOCRUZ 907 strain was tested in four different concentrations, added to the diet; the LFB-FIOCRUZ 856 strain was tested in three concentrations. C. putoria larvae showed sensibility to the treatment with the LFB-FIOCRUZ 907 strain at the tested concentrations. The higher concentration presented the best efficiency, causing higher mortality and reducing larval weight and adult emergence more intensely. The LFB-FIOCRUZ 856 strain showed low toxicity, sliglity reducing emergence time of adults at 326 mg/ 25 g concentration and larval weight at 326 mg/ 25 g and 86 mg/ 25 g concentrations.

Formulations containing the entomopathogenic Bacillus thuringiensis serovar israelensis strain IPS-82 has been widely applied for mosquito control around the world. Strain IPS-82 is highly active against Aedes aegypti but less active against other well-known vectors such as Culex quinquefasciatus and Simulium spp. larvae. Eighteen strains of B. thuringiensis were isolated from Simulium pertinax larvae naturally occurring in rivers of Southeast Brazil with one demonstrating special toxic effects. Simulated field tests against S. pertinax larvae showed that the native Brazilian autoagglutinanting B. thuringiensis (LFB-FIOCRUZ 1035) has an LC50 at least 25 times lower than the standard IPS-82 strain. The same bacterial preparation was also tested against Ae. aegypti larvae in laboratory trials and the LC50 values obtained with LFB-FIOCRUZ 1035 were at least three times lower than the one for the IPS 82 strain. The results indicate that this strain is more toxic than the standard B. thuringiensis serovar israelensis (H14) in the two Dipteran species tested. It is noteworthy that differences between LC50 values were more pronounced in S. pertinax larvae, the source of the original isolation.